Metallocenes are unique in the field of olefin polymerization in that it has been discovered that by changing the substituents on the organic ligands of the metallocene it is often possible to change certain effects that the metallocenes have on the polymerization process. Examples of changes observed following some changes of substituents include polymerization activity, polymer molecular weight, and comonomer selectivity. The process of determining what effect changes in substituents will have is, however, still largely empirical.
An object of the present invention is to provide certain bridged fluorenyl indenyl metallocenes that have improved properties as olefin polymerization catalysts.
Other aspects, objects, and advantages of the present invention will be apparent from the following disclosure.